A Combined Experimental and Theoretical investigation of reactive flow in brittle media with applications to solid Earth geodynamics

自然界和工程界中的许多重要过程都涉及流体渗透到材料中，然后反应形成体积明显更大的新材料。 这些大体积的变化，反过来被认为是诱导压裂开辟了新的途径，流体渗透，可能导致级联的普遍破裂的材料在一个过程中被称为？反应诱导开裂？ 虽然许多自然系统提供了这些过程的间接证据，但人们对这些机制的物理和效率（或者它们是否有效）知之甚少。本建议的目的是通过结合实验室实验，理论和先进的计算模型的反应性脆性材料的反应性开裂过程的基本理解。 对这些过程的更好理解可能会导致新的工程方法，用于有效的碳封存或碳氢化合物提取，可以深入了解诱发地震活动以及自然界中重要的地球科学过程。我们将结合联合收割机实验室岩石力学实验的简化系统与计算模型，可用于测试和验证一系列的水力，机械失效理论与实验的直接对比。实验室实验将在拉蒙？的三轴变形装置，控制流体流动和监测应力，孔隙压力，声发射和渗透率的变化。实验将研究模拟材料的水合和脱水反应，以提供简化几何形状的大体积变化。我们将探讨嵌套圆柱体的材料与内部反应缸，可以产生或摄取含水流体，周围的脆性岩石在不同水平的围压外圆柱体的行为。建模将是哥伦比亚多个部门和学校的合作努力，并使用由PI开发的开源计算框架。实验的直接建模将为检验假设、验证理论、校准本构关系和失效模型提供所需的控制。改进的流体-脆性固体相互作用的理论模型可以扩展到探索它们对大规模地球动力学的影响，例如通过俯冲带的挥发性循环。

Many important processes in the natural and engineered world involve the infiltration of fluids into materials that then react to form new materials with significantly larger volume. These large volume changes, in turn are thought to induce fracturing which opens up new avenues for fluid infiltration, potentially leading to a cascade of pervasively cracked materials in a process dubbed ?reaction induced cracking?. While many natural systems give indirect evidence of these processes, very little is understood about the physics and efficiency of these mechanisms (or if they even work). The purpose of this proposal is to develop a fundamental understanding of the reactive cracking process by combining laboratory experiments, theory and advanced computational models of reactive brittle materials. A better understanding of these processes could lead to new engineering methods for efficient carbon sequestration or hydrocarbon extraction, could give insight into induced seismicity as well important Earth science processes in the natural world.During this award, we will combine laboratory rock mechanics experiments on simplified systems with computational models that can be used to test and validate a range of hydro-mechanical failure theories directly against the experiments. Lab experiments will be conducted in Lamont?s tri-axial deformation apparatus, with control of fluid flow and monitoring of stresses, pore pressures, acoustic emissions and permeability changes. Experiments will investigate both hydration and dehydration reactions on analog materials chosen to provide large volume changes in a simplified geometry. We will explore the behavior of nested cylinders of materials with an interior reactive cylinder that can either produce or ingest hydrous fluids, surrounded by an outer cylinder of brittle rock under various level of confining pressure. The modeling will be a collaborative effort across multiple departments and schools at Columbia and use an open-source computational framework developed by the PIs. Direct modeling of the experiments will provide the needed control for testing hypotheses, validating theories, and calibrating constitutive relations and failure models. Improved theoretical models of fluid-brittle solid interaction can then be extended to explore their consequences for large-scale geodynamics such as volatile cycling through subduction zones.